When you’re passionate about something and deeply committed to seeing it succeed, it can be hard to share control.

However, you’ve probably already realized that when it comes to launching your new business, the “if you want it done right, do it yourself” approach can only get you so far. Starting your own business already means countless long hours and late nights, and attempting to carry the weight alone can easily result in burnout. Plus, the fact of the matter is that no matter how broad your skill set, you’re not going to be an expert at every aspect of running your business. This is especially true if you plan to scale your business quickly; filling every role will be nearly impossible.

However, choosing the person who will help you start and run a business isn’t as simple as selecting a friend you get along with, or someone who thinks your business idea is a good one. Some of the best business partnerships—think Steve Jobs and Steve Wozniak from Apple, or Evan Williams and Biz Stone from Twitter—were noteworthy not only for their success, but also for the way they combined unexpected, complementary skill sets to create unstoppable duos. While not all partnerships remain strong indefinitely (such as in the case of Jobs and Wozniak), a partnership has the power to propel a business to true greatness.

So, it’s a smart move to think carefully before you make this decision, as it’s a crucially important one. We turned to the experts at the Young Entrepreneur Council for their advice on what to look for in a potential business partner; here are the six areas they said were most important.

6 essential traits to seek in a potential business partner

1. Find someone reliable

Let’s start with the obvious—the last thing you want is a partner that can’t be counted on.

“A successful business partnership relies on many things, but trust and reliability are key,” says Greg Mercer of Jungle Scout. “A reliable business partner will share your passion and ambition, challenge you, and bring in new skills and ideas. But most of all, there will always be an element of trust that you are both dedicated to effectively working through any situation together.” When you’re evaluating whether or not to take on a new partner, consider testing their reliability by giving them a bit of “homework” before you make your final decision. This doesn’t need to be anything time-consuming or complicated, but ensure that they are regularly able to deliver on time, that they follow up with you when they say they will, arrive for meetings on time, and so on. You’ll be able to learn a lot from these interactions, and potentially spot any red flags before the partnership is official. If they’re the type to constantly cancel and reschedule at the last minute, for example, that’s probably a bad sign.

2. Seek out complementary personality traits

Remember those noteworthy business partnerships I mentioned earlier? What often made them successful was the perfect combination of complementary traits. Beyond skill sets, look also for partners with complementary personality traits. A founder who is quiet, reserved, and good at one-on-one interaction might do well to find a partner who is more gregarious and enjoys the spotlight. Similarly, a founder who has a tendency to pursue every shiny thing that flits into their path might be well-served to seek out a partnership with someone a little more measured and grounded. “The most important thing you can look for in a business partner is a personality and attitude that works synergistic with your own,” suggests Michael Spinosa of Unleashed Technologies.

Spinosa highlights the ways that complementary personality traits can impact overall company leadership: “Finding the person that is going to help balance the leadership equation for your business is important, not only to the business, but to the employees,” he says. “This approach facilitates a higher level of trust between partners and it permeates throughout the organization.”

3. Find someone that challenges you

“The number one thing to look for in a business owner is someone who will challenge you to be better every single day,” says Suneera Madhani of Fattmerchant. The reality is that you are going to experience days where you feel uninspired, annoyed, and just plain wiped out. One of the benefits of having a business partner on these tough days is that they should be able to reignite your fire. Madhani also notes that having a business partner who challenges you can result in trying different approaches, more creative ways of thinking, and a business that is ultimately stronger. “My business partner and I have the same passion, but different points of view, which helps us make thoughtful, well-rounded decisions about our company,” she says. “Without someone to challenge your way of thinking, you won’t ever realize that your way might not always be the best way.”

4. Prioritize compatibility in terms of business trajectory

Do you and your potential partner have the same vision for the future?

Maybe your plan is to start and run a lifestyle business. You have no interest in quickly selling and exiting your business, but would rather continue to grow at a more measured rate, running your business yourself for as long as it serves you. Considering taking on a business partner? They had better share that same vision. If their goal is to scale quickly and sell, you both are in for a very bad time, as those are completely incompatible end goals and visions for your business. “A successful partnership rows in the same direction,” says Robert De Los Santos of Sky High Party Rentals. “You must be compatible in the shared vision, goal, and purpose of the organization.”

Not only will an incompatible vision create trouble when it comes to deciding on your business’s direction, it will also make it difficult to weather hard times. Finding a business partner with whom you are compatible will make it possible for you to work together to overcome the challenges that crop up during the process of starting and running your business. “Compatibility within a partnership ensures perseverance through difficult times and sustained integrity of the business,” says De Los Santos.

5. Partner with someone who matches your level of obsession

Passion, sure—but obsession?

“I was going to say passion, but that word doesn’t go far enough for me,” explains Bryce Welker of Crush Empire. “I want passionate employees, but I need an obsessive business partner.” For Welker, the difference between passion and obsession lies in one’s need to see something through for the long haul—a quality necessary in a business partner. “If I’m burning the midnight oil, I want them to be right there next to me,” says Welker. “Passion may generate great short-term results, but obsession is what builds lasting empires.”

6. Don’t forget the importance of integrity

Matthew Capala of Search Decoder considers integrity to be the “most important” quality in a business partner who is an equal within your company. “Being honest partners requires honest, clear communication,” says Capala. “Accountability added to honesty is integrity.”

While starting and running your business, both you and your partner are bound to make a few mistakes. “A partner must be accountable for their actions without blaming employees, or outside influences,” says Capala. “Without integrity, you risk triangulating other members of your team, creating disharmony and eventual fissures.”

Just as you would test a potential partner for reliability, consider doing a few small projects with your prospect first to get a sense of their integrity. Do they own up to errors and communicate honestly, or do they fall into a pattern of blame? Find this out early, as a business partner who lacks integrity could wreak havoc for your business down the road.